Hill Therapy

How to train for trail-running's ups and downs

The feel of your heart pounding in your chest at the top of a hill attests to the conditioning hills provide ...

Illustration by Jeremy Collins

The feel of your heart pounding in your chest at the top of a hill attests to the conditioning hills provide for your cardiorespiratory system. But they also provide a great workout for your skeletal muscles. Both uphill and downhill training increase leg muscle power, can be used as a transition into more formal speedwork, improves the performance of the heart and uses the leg, arm and trunk muscles differently than flat running. For trail runners, hills are the place where you can make up the most time in a race.

Why Down Is Harder than Up

If you have ever run a race with long or steep downhills, you know how downhills can trash your legs. Even though running uphill feels harder since your heart must do more work to send blood and oxygen to a large muscle mass working against gravity, downhills cause the biggest impacts on your body.

gravity-induced eccentric muscle contractions force your muscle fibers to lengthen, causing them to tear. Fewer muscle fibers are active compared to other types of muscle contractions, distributing the generated force over a smaller area of muscle and resulting in even more damage.

The forces of impact and braking are also greater during downhill running compared to uphill and flat running, increasing the risk of overuse injury. The muscle damage decreases your muscles' ability to produce force, which slows your pace on the flat and uphill portions of the race and leads to delayed-onset muscle soreness, which includes an inflammatory response and lasts for a few days following the race as your muscle fibers heal.

The good news is that the damaged muscles heal back stronger, protecting them from future injury. Running downhill has a prophylactic effect on muscle damage and soreness. While you can expect your muscles to ache after the first time running downhill, subsequent downhill workouts will cause less soreness.

Downhill running also affects running economy, the amount of oxygen you consume to maintain a given submaximum pace. A number of studies have shown a significant decrease in running economy for up to one week following a 30-minute downhill run on a 10- to 15 percent grade.